One method of controlling a wind power installation is described in DE 195 32 409. Another method of controlling a wind power installation at high wind speeds is described in Erich Hau, ‘Windkraftanlagen’ [‘Wind power installations’], Springer Verlag, 2nd edition, 1996, pages 89 ff and 235 ff.
That known state of the art predominantly describes measures which are adopted to protect wind power installations from overloading, at very high wind speeds. In that respect, in particular mechanical loadings are taken into consideration in order to avoid damage to the installation and/or individual components.
The standard measure described is usually putting the rotor blades into a so-called feathered position. It will be noted however that a necessary condition for that purpose is that there is a possibility of varying the angle of attack of the rotor blades-so-called pitch adjustment. If such a possibility does not exist, a flow breakdown or stall condition is brought about at the rotor blades in order to implement a relief of the load on the wind power installation.
A disadvantage with those known methods however is that no measures are specified for wind speeds which continue to rise, above the first predetermined wind speed, so that it is only possible to trust that the installations are adequately dimensioned to prevent complete destruction of the installation and unavoidable acute endangerment, which this would involve, to the relatively close area around the installation.